Green Car Congress  
Home Topics Archives About Contact  RSS Headlines

« More Japan Gas Stations to Sell 7% ETBE Blend | Main | Aerodynamic Heavy-Duty Truck Trailer Cuts Fuel Consumption and Emissions By Up to 15% »

Print this post

Ford Developing Thermally Sprayed Nano-Coating for Cylinders to Reduce Friction, Support Lighterweight Construction

17 April 2008

Verpoort
Honed cylinder coating made from one of the materials (SUNA) under test. Click to enlarge.

Ford Research Centre Aachen (Germany) is developing a thermally sprayed nano-coating using a Plasma Transferred Wire Arc (PTWA) process that could replace the heavier cast iron liners that provide the necessary wear resistance of cylinder bores in aluminum block engines.

Presented in a paper at the SAE 2008 World Congress by Dr. Clemens Verpoort of the Aachen center, the thin, wear-resistant coating reduces weight and improves friction performance while delivering equal durability and reliability to the product.

Fuel consumption can be reduced by utilizing lightweight construction as well as by decreasing internal friction losses in the drive train.

Modern engine blocks are partly made of cast iron or aluminum material whereas for the later hypo-eutectic AlSi-alloys dominate. Due to the low hardness, surfaces made of these alloys cannot be used as a friction partner for the piston rings. Cast iron liners are often inserted into the engine block to provide a wear-resistant surface for the piston rings. This work describes how cast iron liners can be replaced by thin, nanocrystalline iron based coatings in order to decrease friction losses as well as reduce the engine weight.

—“Thermal Spraying of Nano-Crystalline Coatings for Al-Cylinder Bores”

The process for coating cylinder bores consists of four steps. First is machining the cylinder bore to a certain diameter and then machining the surface so the coating is able to adhere. Next steps are the thermal spraying and the honing of the coated bore to receive a surface that meets tribological requirements.

Four thermal spraying systems are currently either commercially available or under research. One system uses powder feedstock while three of them use wire as feedstock:

  • Rotary powder plasma process (in serial production);

  • Rotating twin wire arc system (in serial production);

  • High velocity oxygen fuel system (under research); and

  • Plasma Transferred Wire Arc system (in serial production).

Verpoort said that the best coatings and most consistent results have been seen with the Plasma Transferred Wire Arc technology, and therefore it was utilized within the framework of the Ford study.

For the study, Ford coated test liners and two Ford Zetec inline 1.4-liter engines with a reference material of 0.1% carbon-steel and an iron-based flux-cored wire feedstock called SUNA. Friction tests were carried out with a stripped down engine. The test can be carried out with or without the cylinder head. For the engine including the cylinder head, the friction with the reference material was 6.8% below the values measured for the standard engine with liners made from grey cast iron. Without the cylinder head, the friction was 14.1% lower compared to the standard engine.

Ford has not tested the SUNA-coated engine yet, but calculated a 10% decrease in friction for the engine including the cylinder head.

The decrease in friction is produced in two ways, said Matthew Zaluzec, manager of the Materials Science & Nanotechnology Department for Ford Research and Advanced Engineering. The first is from the mechanical aspects of honing and sizing the piston and cylinder bore enabled because of the coating, and second is the tribological properties of the lining itself.

The coating study is only one of a larger set of nanomaterials research initiatives spanning applications from paint to engine blocks (and not including the work on electrochemistry and catalysts).

Industry is becoming more efficient at creating nanoparticles. Our challenge is to take those nanoparticles, separate them and disperse them into existing materials in a way that makes our vehicles lighter, more durable, and more fuel efficient.

—Matthew Zaluzec

Ford has called out vehicle weight reduction as a key part of its strategy to improve fuel economy by 40% by 2020 to meet the new CAFE standards. The company’s goal is reduce vehicle weight from 250 to 750 pounds—depending on the model—between 2012 and 2020 without compromising safety.

A Ford study called “Atoms to Engines” looked at the structure of cast aluminum alloys at near atomic levels. From this work, a detailed analysis of the structure/property/process relationship of the aluminum alloy engine blocks has led to reduced engine weight and, in turn, increased fuel efficiency.

Many thought our aluminum engine technology was mature and fully optimized. Not until we looked at every aspect of the materials and manufacturing process were we able to pull out another 10 percent in structural performance out of our engines, which directly translates into weight and fuel economy savings year over year. It’s nano at the working level.

—Matthew Zaluzec

In 2007, Ford formed an alliance with Boeing and Northwestern University in Evanston, Ill., one of the early leaders in the field of nanoscience and home to one of the first nanotechnology centers in the country. (Earlier post.) The alliance, which was created to research commercial applications of nanotechnology, is producing results in the areas of specialty metals, plastic composites, thermal materials, coatings and sensors that could have large-scale uses across the transportation industry in the future.

Resources

April 17, 2008 in Engines, Materials, Nanotech | Permalink | Comments (15) | TrackBack (0)

TrackBack

TrackBack URL for this entry:
http://www.typepad.com/services/trackback/6a00d8341c4fbe53ef00e551f1e9668834

Listed below are links to weblogs that reference Ford Developing Thermally Sprayed Nano-Coating for Cylinders to Reduce Friction, Support Lighterweight Construction:

Comments

I heard a guy mention Kyocera was working on a ceramic engine. The temperatures and efficiency would be higher. I would imagine that there are some technical hurdles to be overcome.

It sounds like after the thin coating has worn off the underlying Al would wear quickly.
Reduced friction is good and all that but it sounds like this would result in a disposable engine, one that can't ever be overhauled.

Just like GM's Vega all over again. At that time it was silicon embedded in the aluminium cylinder walls. Best thing is to embrace EV's and skip the engines all together.

You guys thinking the same thing I was. The sad think is if they build it people will buy it. The wrecking yard will be full of them. Just the same as the cycle the Vega went though.

@sjc

Ceramic engine? What about durability? I thought the pliability of metals is what made them such a great material for use in a high vibration environment e.g. an engine.

"I heard a guy mention Kyocera was working on a ceramic engine. The temperatures and efficiency would be higher. I would imagine that there are some technical hurdles to be overcome."

http://en.wikipedia.org/wiki/Ceramic#Other_applications_of_ceramics

"In the early 1980s, Toyota researched production of an adiabatic ceramic engine which can run at a temperature of over 6000 °F (3300 °C). Ceramic engines do not require a cooling system and hence allow a major weight reduction and therefore greater fuel efficiency. Fuel efficiency of the engine is also higher at high temperature, as shown by Carnot's theorem. In a conventional metallic engine, much of the energy released from the fuel must be dissipated as waste heat in order to prevent a meltdown of the metallic parts. Despite all of these desirable properties, such engines are not in production because the manufacturing of ceramic parts in the requisite precision and durability is difficult. Imperfection in the ceramic leads to cracks, which can lead to potentially dangerous equipment failure. Such engines are possible in laboratory settings, but mass-production is unfeasible with current technology."

eric,

Thanks for the research. I would say that a ceramic turbine would suffer the same fate. Somehow, I can not imagine that steel cylinder sleeves are all that much trouble in aluminum engines so far.

I was reading that Honda double honed their hybrid engine and offset the wrist pin to reduce loses. They continue to improve the ICE, but at some point it will take more to yield less. The simplicity of EVs and FCs starts to look better over time.

Another problem might be the incompatability of the iron-based lining material with the aluminium block. Fracturing at the interface could loosen the liner fitting. Has any durability testing been done with a real operating engine (the article says the research used a stripped down engine)?

GM didn't use silicone aka bathroom sealant, it used silicium scaffolding in the casting technology. It may not have worked at the time because the casting process could not be simulated in detail on computers. Today, that is possible and VW & Audi are using essentially the same concept on all of their aluminum engine blocks, with great success. Note that they use hypereutectic Al-Si, though. The honing process breaks out silicium crystals in the surface, creating tiny pockets in which oil can accumulate to provide just enough lubrication.

Ford uses a cheaper, simpler casting process. Their preference was for the application of coatings, which is fine as long as they are durable.

Both strategies are intended to reduce piston slap, blow-by and oil wear/loss by giving block and piston the same thermal coefficient of expansion. In conventional approaches, the piston suffers from excessive clearance after a cold start as it must be allowed to expand more than the cast iron liner or block during warm-up.

The Vega was a brilliant design, just poorly executed. At the time I owned like 15 of them :)

I tought the coating was teflon?

Ceramic will make a comeback I am pretty conviced of that, especially on diesel or Atkison cycle where most of the heat is lost in the coolant. In the 80s the ceramic industry was not mature enough, and in 86 thee oil price collapsed so why bother with ceramics at the time.

Those higher temperature could make high grade heat recovery more efficient as well. If the engine runs above 1000f, there is a lot of high temperature heat to tap.

Porsche has been using the nikasil coatings for many years, it doesnt wear and its real hard to damage. Its also used in many racing engines for the same reason.Ford would rather reinvent the wheel than use existing technology ( and pay royalties).

"GM didn't use silicone aka bathroom sealant, it used silicium scaffolding in the casting technology. It may not have worked at the time because the casting process could not be simulated in detail on computers. Today, that is possible and VW & Audi are using essentially the same concept on all of their aluminum engine blocks, with great success. Note that they use hypereutectic Al-Si, though. The honing process breaks out silicium crystals in the surface, creating tiny pockets in which oil can accumulate to provide just enough lubrication.

Ford uses a cheaper, simpler casting process. Their preference was for the application of coatings, which is fine as long as they are durable."

I would like to add that VW uses a plasma coating process on their aluminum block V10 Diesel. I believe the Al-Si block is a recent technology to be implemented by VW/Audi.

Jason

"GM didn't use silicone aka bathroom sealant, it used silicium scaffolding in the casting technology. It may not have worked at the time because the casting process could not be simulated in detail on computers. Today, that is possible and VW & Audi are using essentially the same concept on all of their aluminum engine blocks, with great success. Note that they use hypereutectic Al-Si, though. The honing process breaks out silicium crystals in the surface, creating tiny pockets in which oil can accumulate to provide just enough lubrication.

Ford uses a cheaper, simpler casting process. Their preference was for the application of coatings, which is fine as long as they are durable."

I would like to add that VW uses a plasma coating process on their aluminum block V10 Diesel. I believe the Al-Si block is a recent technology to be implemented by VW/Audi.

Jason

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Working...
Your comment could not be posted. Error type:
Your comment has been posted. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.

Working...

Post a comment

Green Car Congress © 2017 BioAge Group, LLC. All Rights Reserved. | Home | BioAge Group